Head to Head
| World Championship 2020 | 2020/08/11 18:00 | Mark Williams v Ronnie O'Sullivan | 10-13 |
| Gibraltar Open 2019 | 2017/11/16 11:30 | Ronnie O'Sullivan v Mark Williams | 5-1 |
| UK Championship | 2016/12/02 19:00 | Mark Williams v Ronnie O'Sullivan | 2-6 |
| Championship League Snooker | 2016/01/04 12:00 | Ronnie O'Sullivan v Mark Williams | 3-2 |
Home History
| European Masters 2020 | 2020/09/24 18:00 | Aaron Hill v Ronnie O'Sullivan | 5-4 |
| UK Championship 2020 | 2020/09/21 08:43 | Stephen Hendry v Ronnie O'Sullivan | 0-0 |
| World Championship 2020 | 2020/08/15 12:30 | Kyren Wilson v Ronnie O'Sullivan | 8-18 |
| World Championship 2020 | 2020/08/14 18:00 | Ronnie O'Sullivan v Mark Selby | 17-16 |
| World Championship 2020 | 2020/08/11 18:00 | Mark Williams v Ronnie O'Sullivan | 10-13 |
| World Championship 2020 | 2020/08/09 18:00 | Ding Junhui v Ronnie O'Sullivan | 10-13 |
| World Championship 2020 | 2020/08/07 18:00 | Ding Junhui v Ronnie O'Sullivan | 10-13 |
| World Championship 2020 | 2020/08/02 13:30 | Ronnie O'Sullivan v Thepchaiya Un-Nooh | 10-1 |
Away History
| European Masters 2020 | 2020/09/24 09:00 | Mark Williams v Peter Devlin | 4-5 |
| European Masters 2020 | 2020/09/21 09:00 | Mark Williams v Ashley Hugill | 5-0 |
| World Championship 2020 | 2020/08/11 18:00 | Mark Williams v Ronnie O'Sullivan | 10-13 |
| World Championship 2020 | 2020/08/07 09:00 | Mark Williams v Stuart Bingham | 13-11 |
| World Championship 2020 | 2020/07/31 18:00 | Mark Williams v Alan McManus | 10-5 |
| Gibraltar Open 2020 | 2020/03/15 15:00 | Kyren Wilson v Mark Williams | 4-0 |
| Gibraltar Open 2020 | 2020/03/15 12:10 | David Grace v Mark Williams | 1-4 |
| Gibraltar Open 2020 | 2020/03/15 09:00 | Tian Pengfei v Mark Williams | 3-4 |